Genome-Wide Identification and Characterization of the VOZ Gene Family in Gossypium hirsutum L. and Functional Characterization in Abiotic Stress and Somatic Embryogenesis.

Vascular Plant One-Zinc finger (VOZ) transcription factors are pivotal regulators of plant growth and stress adaptation, yet their functional roles in Gossypium hirsutum, a key fiber crop, remain poorly characterized. In this study, we systematically identified six VOZ genes in G. hirsutum and conducted a comprehensive analysis of their phylogenetic relationships, genomic distribution, promoter architecture, and expression profiles. Phylogenetic classification placed the GhVOZ proteins into three distinct clades, and chromosomal localization revealed that family expansion was likely driven by segmental duplication events. Promoter analysis uncovered an abundance of stress-related cis-regulatory elements, suggesting a potential role in abiotic stress signaling. Consistent with this, expression profiling demonstrated that GhVOZ1/3, GhVOZ2/4/5, and GhVOZ6 were specifically induced under drought, salt, and cold stress, respectively, with qRT-PCR further confirming their tissue-specific dynamic regulation under salt treatment. Furthermore, the GhVOZ family exhibited stage-specific expression patterns during somatic embryogenesis. GhVOZ1, GhVOZ3, and GhVOZ4 were upregulated at the early induction phase, implicating them in the initiation of cell reprogramming. In contrast, GhVOZ2 and GhVOZ4 showed sustained expression in embryogenic callus at later stages, suggesting a role in maintaining embryogenic competence, whereas GhVOZ5-preferentially expressed in non-embryogenic callus-may act as a repressor of embryogenesis. Synteny analysis further highlighted evolutionary conservation and subgenomic divergence of VOZ genes in G. hirsutum. Collectively, these findings establish GhVOZs as key regulators integrating abiotic stress response and somatic embryogenesis, providing a genetic framework for future functional studies and crop improvement.